Tanner Houck’s originally scheduled start on Monday was pushed back after the Red Sox right-hander didn’t bounce back as well as hoped following his previous outing.

Tuesday, manager Alex Cora revealed that Houck is specifically dealing with fatigue in his throwing shoulder.

“Just the shoulder not bouncing back,” Cora said. “Nothing like to be alert, but be smart about it.”

Cora said Houck is feeling better and for now the plan is still for him to make his next start in Friday against the New York Yankees. Houck has already blown past his career-high in innings pitched, but he’s remained effective into the second half, posting a 3.79 ERA over his last six starts dating back to Aug. 9.

If Houck isn’t able to go, his upcoming start would be filled by Richard Fitts, who was called up over the weekend and made his MLB debut on Sunday against the Chicago White Sox. Fitts went 5.2 innings and allowed two unearned runs in his first big league start, and he wasn’t optioned back to Triple-A following the game, an indicator the club believes he may still be needed in the near future.

Would that be as insurance for Houck or possibly as part of a six-man rotation? Cora said the club isn’t in a position to say.

“Not yet,” Cora said. “Tanner, obviously that and where we’re at today, so we’ll see.”

Injury updates

Liam Hendriks (Tommy John rehab) played catch on Monday but has made no mound progression since suffering a setback in his recovery last week. … Having played two straight games after being activated from the injured list after five months on the shelf, Trevor Story was given the day off Tuesday. … Cora had no update on left-hander Cam Booser (left elbow inflammation), who is expected to be activated in the coming days.